Gokay, a while back I posted a teaser about me not being dead but just busy. Well, I finally have the time to share what I did during those 2 weeks. Along with the many other projects I did in the “Crazed 2 weeks of Spooph fondling his 2fiddy” I installed steel braided lines and cleaned, inspected and painted the calipers. The steel braided line install is what started a “while I’m in there, I might as well do this” progression which eventually turned into mayhem. I’ll be posting the other changes/maintenance and modification I did to the bike in the next few days. This is fairly specific to a Ninja 250, but should be applicable to most other bikes.
I started with the rear brake. This might be easier with the rear wheel removed. It is possible to remove the rear caliper without removing the rear wheel, but it’s a bit of a PITA getting the hex-head socket into the 2 mounting bolts that hold the caliper to the caliper bracket, which is held to the swing arm by a rail and the pressure of the rear wheel being in place. At this point, it’s time to make a decision – drain the brake system as much as possible with everything in tact, and it will be less messy, or unbolt the caliper and wipe up any juice that spills. The system could also be removed in it’s entirety, but then all the parts have to be pinched in a vice to get the bolts loose. I opted to just take it apart and catch any of the highly corrosive brake fluid that flows out.
Undo the hose leading to the caliper:
Remove the caliper:
The rearsets can be removed at this point in order to remove the rear brake master cylinder for a full cleaning and rebuild. I was too lazy to do this because I rarely use the rear brakes and felt it not necessary. I simply installed braided steel lines on the rear brakes for aesthetic reasons anyway, and I’ve never felt them fade…
Now is an easy time to further drain the system and get the master cylinder empty, which means less brake fluid will leak out onto the swing arm and exhaust.
First remove the reservoir cap to allow the system to breath freely:
Make sure to remove the rubber expansion seal:
Store the cap, plastic pressure washer and rubber expansion seal together so nothing gets lost or hurt:
Now drain the system by pumping the rear brake until no more fluid comes out:
Then remove the brake line from the master cylinder by removing the banjo bolt, as you did with the caliper.
It might be a good idea to wrap a rag around the area to catch any fluid that WILL leak out.
I then moved onto removing the front caliper, being that I wanted to paint both of them at the same time. Before removing the caliper, brake the pad retention pins loose. These suckers get tight, and it’s easier to do on the bike. For the rear caliper I’ll have to clamp it in a vice to get them loose because they’re a PITA to get to while the rear caliper is on the bike.
Dirty dirty dirty calipers!
2 brake pad retention bolts removed, 2 brake pads removed, 2 caliper bracket (attachment to forks) loosened, soon to be removed, and 1 hose guide bent open to remove line. You could also remove the line from caliper and feed it through, but that’s messier than I’d liked… There is also a reason I’m doing this, bare with me. At this point, the front brake system is removed from the bike as a solid unit.
Next it’s time to brake loose the front brake reservoir/master cylinder unit screws to get to the fluid inside. If they don’t come loose easily, find a screw driver that fits them nicely and hit it with a hammer. Don’t be shy, HIT IT! They will loosen up considerably.
If that doesn’t work, clamp it in a vice, use the same proper fitting screw driver and a pair of vice grips to attain the required slow-steady force to remove these suckers. No matter how carefully I put them in, they always do this to me. It’s always a struggle. Why? Because steel and aluminium fuze together in what’s called a “cold weld”. A cold weld is where Aluminium microscopically molds itself to the steel because it’s softer. The heating and cooling of the reservoir being in the sun, in addition to the heat generated by the system from regular use aids in this “welding”. This means… MORE FORCE!
I ended up damaging the screws a bit, but not enough to require replacements in my book:
mmmmmmm, delicious 2 year old, 40K mile abused brake fluid!
To completely clean the calipers, I must remove the pistons which transfer the braking force onto the pads. They are stuck in there, even when they’re moving freely. You can either empty the system and blow it out with compressed air, or you can use the system with the brake fluid in place to push them out, depending what you have available to you:
One piston will move more than the other, it’s inevitable. You might also have to hold the piston in place as you feed in more and more brake fluid. Use a C-clamp to HOLD the motivated piston at bay while you push the other one equally. DO NOT CLAMP IT BACK DOWN, as you would when replacing the pads, just barely holding is fine.
Ah, getting closer to equality:
And freedom, this is a bit messy, as is usually the case with freedom:
At this point you could remove the front caliper and attach the rear caliper to the master cylinder to use the same technique to remove its pistons. Luckily I had an air compressor available (which makes things much easier and faster). I simply used the master-cylinder technique as an illustration to those who might not have access to a compressor. Of course, if your pistons are stuck because you neglected them more than I did these, a compressor might not have enough oomph to push them out, at which point, the master-cylinder method will probably do the trick, albeit slower. Whatever you do, DO NOT GRIP THE PISTONS WITH A PAIR OF PLIERS AND PULL. YOU WILL DAMAGE THEM BEYOND REPAIR.
So at this point I remove the line from the master cylinder:
And the caliper:
And then proceed to disassemble the caliper as far as it will go – bleeder nipple:
The front caliper’s mounting bracket just slides out of the greased rubber slides. Just keep pulling, it will eventually slide out. These little rods are what allows the caliper to float back and forth on the disc, yielding even brake pad wear. If you’re brake pads are wearing unevenly, it’s because these guys don’t have a smooth action. Lube it up and test to make sure everything moves smoothly.
Mounting bracket and rubbers removed. The short one at the top just pops out. I found it easier to squish the closed end of the longer rubber and push it through that way, rather than the larger thicker, ridged end…
Master cylinder dissasembly. Pull rubber seal off master cylinder. I used a VERY small screw driver to carefully pry the top lip off the rod, at which point you can just pull and the bottom lip will just pop free:
Although fuzzy, you can see the top lip ontop of the rod, and the bottom lip free. If it’s not wanting to pull, use the same screw driver just as gingerly and wiggle it free. Do your best not to push a hole into it or to damage it in ANY way:
Next, the Jesus clip, otherwise know as a c-clip. C-clip because it looks like a C. Jesus because every time you try and remove or replace one of these you loose your grip on it and it goes flying off into some c-clip black hole at which point you exclaim “Jesus” in frustration. Then, for using His name in vain, He makes sure you never find it again. To remove the c-clip you’ll need very fine needle nose pliers, or a special round-nosed c-clip set of pliars.
And master cylinder piston comes boinging out..
I didn’t want to scrub. I was lazy. So I got myself a bunch of pinesol and put everything into a tub full of it and let it soak a few days. I had to paint the calipers anyway, so it wasn’t like I was in a rush. Many people will tell you that Pinesol will harm the seals on the calipers. This might be true, but I left my calipers with their seals in the stuff for almost 2 weeks, and they haven’t leaked yet. I’m saying use the stuff, but I’m not saying don’t use it either…
There, everything is now disassembled. You can clean, paint, replace pistons seals in the calipers, etc, etc to your hearts content. Assembly is the reverse (can you tell I read the maintenance manual a lot ).
A few notes on reassembly: Make sure to assembly the entire system on the bike, and DON’T TIGHTEN ANYTHING UNTIL IT ALL FITS PERFECTLY. If you need to bend banjo bolts, use a vice and a hammer with accurate strikes. Never bend a banjo bolt more than 10 degrees. It will snap. Unless you have A LOT of heat. I doubt propane could get it hot enough to bend sharper than that. That’s why they sell them in various pre-bends. Buy the right ones!
A few notes on bleeding the system: With a completely empty system there isn’t enough drag to keep fluid staying in the system, you have to give it some negative pressure. If you’re brave/stupid, like me, you could use the bleed tube (I use just some clear tubing that fits the bleeder nipples from my local hardware store), and suck on it until you can suck no more. That provides ample negative pressure in the system and enough drag to keep the fluid flowing forward (from master cylinder to caliper) and eases the job considerably. However, brake fluid is very corrosive and VERY poisonous. Make sure you have a clean tube with plenty of length so you can remove your mouth before the juice gets anywhere near it… Yea yea yea, I purposefully wrote the innuendos. I hope you enjoy them! OR OR OR, you could buy yourself a “Speed bleeder” from amazon or many other places on the net which does the exact same thing, except your forearm will get a workout as opposed to your mouth. Wow, I shouldn’t write these things 3 beers in with too little sleep, my mind goes right to the gutter…
Anyway, I hope this helps and that I didn’t offend anybody too much. Feel free to ask questions. I didn’t write this to be a step-by-step specifically, but more so to increase your understanding of the system if you didn’t already have it so you can know what’s going on, and adapt it to your tools/resources/abilities.